- "Sonic and "Tails" in" instead of miles tails prower blabla.
- The sound isn't stopped if the game is paused.
- Only Up and Down works at the level select.
- Sound test option at level select is a bit messed up (until you highlight it):

- "Option" instead of "Options".
- "Sonic only" and "Tails only" instead of xx alone.
- No Hidden palace, no wood zone, similar to the final. To be checked more comprehensively.

this is the first Sonic 2 prototype where Debug actually WORKS =P
Eggman's Final huge Robot thing still starts in the center
The laser sound effects that hit Tails plane are slightly different.
Boss music doesn't play during WFZ boss
when Sonic jumps onto the biplane at the end of WFZ the jump sound plays twice for some reason

That happens in the Wai build too, haven't personally tested it in NA so dunno. Easiest place to try it in NA/Wai is at the start of HPZ, just run to the right and then press down to roll. Sonic will die and there's a good chance Tails will do exactly what he did in that video.

LocalH I tried to do the same thing on the Wai Proto and cant do it. Tails behaves in a completely different way because he tries to mimmick Sonic's every move rather than semi intelligently following him.

It probably depends on Sonic's speed at the time given the difference in Tails' behavior. It's definitely there though in the Wai build, because we knew about that LONG ago. Interesting to see how late in development it lasted, though.

Yeah, it's there, it's actually easy to see it. Do the following: Select HPZ, and right when the title card dissappears, spindash to the right. When the death animation is being shown press a; since tails mimic the key presses, he will jump and hit the bandik, causing the bug.